do you need a new key and transponder $7.oo

found this site
http://s.dealextreme.com/search/nissan+transponder
alot cheeper than mr nissan
Just remove chip from old key and insert in new housing
or if you want to reprogram it NIZZBITS DID THIS
I did this for a bloke yesterday so while it is fresh in my mind this is how you do it.
Get in and close the door (all doors closed of course).
Lock the doors with the button on the driver door inner handle.
Slide the key in and out about 5 or 6 times. When you get to the right amount of times the doors will unlock. I can't remember if I left the key in or out but I don't think it matters. Out would be my first guess.
Lock the doors with the inner handle button again. (NOT DOING THIS BIT IS THE FATAL MISTAKE SOME MAKE)
Push the unlock button on the remote.
If it works the doors will unlock and you are away.

Took me three or four goes yesterday but practise and patinece is all it takes usually. I have had them refuse to work though and then you need a dealer to try it. Only thing I would worry about is if it is a few years old and not used the battery could be cactus or the circuit board dried and buggered. Give it a go. Nothing to lose.